- Hydroencephalocele (congenital) 742.0
- Hydroencephalomeningocele (congenital) 742.0
- Hydrohematopneumothorax (see also Hemothorax) 511.8
- Hydromeningitis - see Meningitis
- Hydromeningocele (spinal) (see also Spina bifida) 741.9
- Hydrometra 621.8
- Hydrometrocolpos 623.8
- Hydromicrocephaly 742.1
- Hydromphalus (congenital) (since birth) 757.39
- Hydromyelia 742.53
- Hydromyelocele (see also Spina bifida) 741.9
- Hydronephrosis 591
- Hydropericarditis (see also Pericarditis) 423.9
- Hydropericardium (see also Pericarditis) 423.9
- Hydroperitoneum 789.5
- Hydrophobia 071
- Hydrophthalmos (see also Buphthalmia) 743.20
- Hydropneumohemothorax (see also Hemothorax) 511.8
- Hydropneumopericarditis (see also Pericarditis) 423.9
- Hydropneumopericardium (see also Pericarditis) 423.9
- Hydropneumothorax 511.8
- Hydrops 782.3
